Ambrisentan should not be used to treat patients for idiopathic pulmonary fibrosis (IPF).
IPF is a fatal form of chronic, progressive lung disease characterized by irreversible scarring around both lungs. IPF causes about 5,000 deaths each year and currently there is no approved treatment. Researchers do not know what causes IPF, but a protein called endothelin-1 that causes the blood vessels to contract and induces lung scarring and proliferation has been associated with the disease.
Researchers sought to determine if ambrisentan, a selective endothelin receptor antagonist, could reduce the rate of IPF progression.
The authors enrolled patients between 40 and 80 years with IPF and minimal or no honeycombing (a pattern of lung fibrosis associated with advanced disease) on high-resolution computed tomography scans. Patients were prescribed ambrisentan 10mg/d or placebo to assess time to disease progression as defined as death, respiratory hospitalization, or decreased lung function.
The study was terminated after nearly 35 weeks and enrollment of 492 patients (75 percent intended enrollment) due to the low likelihood of showing efficacy by the end of the study. The researchers found that patients treated with ambrisentan actually had shorter time to disease progression and were more likely to require hospitalization.